NEW DELHI (AFP) - A former Indian government minister went on trial amid chaotic scenes on Friday, accused of playing a central role in a massive corruption scandal over the allocation of mobile phone licences. A. Raja, who was telecoms minister from 2007 to 2010, is the central figure in a case that has rocked Prime Minister Manmohan Singh's administration and helped make corruption one of the country's hottest political issues. The sale of second-generation (2G) licences at far below their commercial rate to selected companies could have cost the treasury up to $40 billion in lost revenue, according to the public auditor. Raja appeared alongside the other 13 defendants from the senior ranks of telecom companies.